The present invention provides for a mechanism to completely replace the electron accepting function of glycerol formation with an alternative pathway to ethanol formation, thereby reducing glycerol production and increasing ethanol production. In some embodiments, the invention provides for a recombinant microorganism comprising a down-regulation in one or more native enzymes in the glycerol-production pathway. In some embodiments, the invention provides for a recombinant microorganism comprising an up-regulation in one or more enzymes in the ethanol-production pathway.

Presented herein are biocatalysts and methods for converting C1-containing materials to organic acids such as muconic acid or adipic acid.

A recombinant yeast cell, fermentation compositions, and methods of use thereof are provided. The recombinant yeast cell includes at least one heterologous nucleic acid encoding one or more polypeptide having phosphoketolase activity; phosphotransacetylase activity; and/or acetylating acetaldehyde dehydrogenase activity, wherein the cell does not include a heterologous modified xylose reductase gene, and wherein the cell is capable of increased biochemical end product production in a fermentation process when compared to a parent yeast cell.

Described is a method for the production of D-erythrose and acetyl phosphate comprising the enzymatic conversion of D-fructose into D-erythrose and acetyl phosphate by making use of a phosphoketolase. The produced D-erythrose can further be converted into glycolaldehyde by a method for the production of glycolaldehyde comprising the enzymatic conversion of D-erythrose into glycolaldehyde by making use of an aldolase, wherein aldolase is a 2-deoxyribose-5-phosphate aldolase (EC 4.1.2.4) or a fructose-bisphosphate aldolase (EC 4.1.2.13). The produced glycolaldehyde can finally be converted into acetyl phosphate by the enzymatic conversion of the thus produced glycolaldehyde into acetyl phosphate by making use of a phosphoketolase or a sulfoacetaldehyde acetyltransferase.

Genetically engineered cells and methods are presented that allow for the production of various value products from CO.sub.2. Contemplated cells have a CBB cycle that is genetically modified such that two molecules of CO.sub.2 fixed in the CBB cycle can be withdrawn from the modified CBB cycle as a single C2 compound. In contemplated aspects a CBB cycle includes an enzymatic activity that generates the single C2 compound from a compound of the CBB cycle, while further modifications to the CBB cycle will not introduce additional recombinant enzymatic activity/activities outside the already existing catalytic activities in the CBB cycle.

Described are recombinant microorganisms characterized by having phosphoketolase activity, having a diminished or inactivated Embden-Meyerhof-Parnas pathway (EMPP) by inactivation of the gene(s) encoding phosphofructokinase or by reducing phosphofructokinase activity as compared to a non-modified microorganism and having a diminished or inactivated oxidative branch of the pentose phosphate pathway (PPP) by inactivation of the gene(s) encoding glucose-6-phosphate dehydrogenase or by reducing glucose-6-phosphate dehydrogenase activity as compared to a non-modified microorganism. These microorganisms can be used for the production of useful metabolites such as acetone, isobutene or propene.

Aspects of the disclosure are directed to genetically modified yeast cells and methods for use. Certain aspects are directed to recombinant yeast cells comprising exogenous nucleic acid sequences encoding phosphotransacetylase and/or phosphoketolase proteins, including a phosphoketolase protein from Clostridium acetobutylicum. Also disclosed are methods for generating recombinant yeast cells and methods of use of such cells for production of one or more products, including lipids, oils, fatty acids, and triacylglycerides.

The present disclosure concerns a symbiotic combination of a bacterial host cell and a yeast host cell selected or engineered to utilize glycerol to reduce greenhouse gases during the production of ethanol from a biomass comprising pentoses.

The present disclosure concerns a symbiotic combination of a bacterial host cell and a yeast host cell selected or engineered to utilize glycerol to reduce greenhouse gases during the production of ethanol from a biomass comprising hexoses.

The disclosure provides polypeptides and encoding nucleic acids of engineered phosphoketolases. The disclosure also provides cells expressing an engineered phosphoketolase. The disclosure further provides methods for producing a bioderived compound comprising culturing cells expressing an engineered phosphoketolase.